Abdallah Hayar, Ph.D.

Major Interests
Role of synchronized bursting activity in olfactory bulb processing of sensory input.

Research Interests
Our neurons convey information to each other via chemical and electrical synapses and perform computations that are vital to our survival. My main research interest is to investigate synaptic transmission and function in different brain networks. I am interested in particular in the processing of sensory information in the olfactory bulb. The olfactory bulb has become an attractive model to study cellular mechanisms underlying the encoding, transfer, processing and decoding of sensory information. Interest in this area was sparked by a series of dramatic breakthroughs over the past decade in our understanding of the organization and function of the peripheral olfactory system, cloning of the olfactory receptors, and identification of the olfactory transduction machinery. These advances have set the stage to unravel the mechanisms of early sensory processing by bulbar circuits. In addition, there has been recently an increase of interest in olfactory dysfunction because the impairment of olfactory bulb seems to be associated with Alzheimer’s and Parkinson‚s diseases. The cellular and molecular mechanisms underlying olfactory dysfunction in these neurodegenerative diseases remain unknown. My main research interest is to investigate the synaptic organization of olfactory bulb glomeruli and the role of glomerular circuitry in olfactory coding in normal and pathological states. We recently found that olfactory bulb external tufted cells are endowed with spontaneous rhythmic bursting. Using simultaneous patch-clamp recordings from pairs of neurons, we were the first to discover that membrane potential oscillations and spontaneous bursting activity are highly correlated in cells associated with the same glomeruli. Synchronous bursting may play an important role in olfactory coding and in regulating the induction of synaptic plasticity at the first input stage of the main olfactory bulb. In summary, the purpose of this project is to unravel the fundamental network mechanisms responsible for encoding and processing odor information. For more information on Dr. Hayar‚s research, see his website at http://hayar.net